Anti-sloughing bobbin



June 25, 1963 R. ATWOOD ETAL 3,095,161

ANTI-SLOUGHING BOBBIN Filed Aug. 1, 1957 FIG. 3.

GROOVE INVENTORS fl n-o1 a130 M 4. a dz y United States Patent 3,095,161ANTI-SLOUGHING BOBBIN Rawson Atwood, Rumson, and Charles C. LAllemand,Murray Hill, NJ. Filed Aug. 1, 1957, Ser. No. 675,739 1 Claim. (Cl.242-159) This invention relates to improvements in textile bobbins.

More particularly, the invention is concerned with providing an improvedbobbin surface which minimizes sloughing or axial movement of yarn alongthe bobbin as it is being wound.

A bobbin embodying the invention in a preferred form will now first bedescribed with reference to the accompanying drawing, the featuresforming the invention will then be pointed out in the appended claim.

In the drawing:

FIG. 1 is a side elevation of a bobbin embodying the invention in apreferred form;

FIG. 2 is an end elevation of the bobbin of FIG. 1;

FIG. 3 is an axial section of the bobbin of FIG. 1;

FIG. 4 is a much enlarged developed elevation view of a part of thesurface of the bobbin, generally within the area indicated by the circle4-4-4 of FIGURE 1; and

FIG. 5 is a section on the line 55 of FIG. 4.

The improvement of the invention is applicable to bobbins with a greatvariety of surfaces, structures, sizes and proportions. However, fordefiniteness and by way of example, the bobbin is shown herein with somecompleteness.

Referring to FIGS. 1-3, inclusive, the bobbin illustrated is generallyof the type shown in our previous application Serial No. 494,405, filedMarch 15, 1955, now Patent No. 2,953,317, for Spool. The bobbincomprises an inner barrel member 1, which may be of sheet steel or othermaterial possessing the required strength, a drive end fitting 2, a topend fitting 3 and a plastic outer barrel or covering 4. The major partof the outer surface of the barrel is, however, specially constructed ortreated over the shaded area 5 to minimize sloughing or axial move-[HlBIlt of the yarn. While sloughing creates more of a problem in thelower deniers and in filaments such as nylon, the invention has beenfound to be of utility within a denier range of 15 or even lower, up to70 denier or even higher, and is of utility w'thout regard to thespecific ma terial of which the filament or yarn may be composed, andwherever difiiculty due to sloughing is experienced.

The cover 4 of the spool illustrated is roughened or ridged over thearea 5 in a manner so as not to interfere with the winding or unwindingof the yarn, while preventing axial slippage. The preferred form ofsurface roughening is shown on a much enlarged scale in FIGS. 4 and 5.As there shown, the surface of the bobbin is circumferentiallymicrogrooved. In the specific embodiment shown, the groove takes theform of a helix having an axial pitch or spacing between grooves ofabout 128 to the inch, so that the indicated distance is in theneighborhood of .008 inch. The groove itself may vary in dimensions, butit has been found in practice that a groove having a depth of about .002or even less is satisfactory. A microgroove of this type does notdisturb the desirable surface characteristics of the bobbin in any wayand efiec- 3,095,161 Patented June 25, 1963 ice tively prevents anyobjectionable sloughing or axial movement of the yarn.

The invention in its broader aspect is not limited to any particularconstruction of bobbin, as for example, to a bobbin composed of metalinner barrel with plastic covering, but is applicable also to molded orturned bobbins made of any of various materials, provided they may besuitably microgrooved either by cutting, molding or pressing the groovein the surface of the bobbin.

In the particular bobbin shown by way of example, the plastic cover iscomposed of an acrylonitrile copolymer such as marketed under the tradename Kralastic, although a variety of other thermoplastic orthermosetting resins may be employed. With this material, the cover 4may conveniently be manufactured in the form of tubing and themicrogroove may be pressed into the surface by means of a suitablygrooved metal die.

The precise size and pitch of the microgroove may be selected withreference to the manufacturing processes employed to produce it, thecharacteristics of the material of which the bobbin surface is composedand the class of service for which the bobbin is used. It will be notedthat the size of the groove may be and preferably is very small withreference to even very fine yarns, as even 15 denier filament has adiameter of about 1.7 mills, while 60 denier filament has a diameter ofabout 3.4 mills. In general, the pitch or axial spacing between adjacentgrooves is at least equal to and preferably is two to four times thethickness of the filament, while the groove itself has a depth and widthwhich may be a very small fraction of even a very fine yarn or filamentdiameter. For example, a groove at a depth of .0002 has a depth andwidth amounting to only about 15% of the diameter of even a finefilament such as 15 denier nylon. In general, grooving having a depth ina range from about .0001 to .001" can be manufactured in a practicalmanner and furnish resistance to sloughing while not interfering withwinding the yarn. In consequence, the characteristics of the bobbin sofar as winding and unwinding of the yarn are concerned are practicallyunafiected and the surface is to all intents and purposes a smooth one.However, the grooving presents sufficient resistance to axial movementof yarn in contact with the bobbin surface to prevent sloughing in avery effective manner.

The preferred method of microgrooving the bobbin surface consists inplacing the plastic cover tube in a cavity die having a sharp V-threadof the desired pitch, in the case illustrated by way of example, 128threads to the inch, and expanding the plastic tube outwardly againstthe cavity die under a pressure of 3,000 6 ,000 psi The cover tube ofthe indicated acrylonitrile plastic and the wall thickness of .02. inchmay be indented in this manner very readily. Under these conditions,there may be an indicated bite of the thread into the outer surface ofthe plastic of about one-half a thousandth of an inch, resulting in agroove of somewhat less than this depth and depending upon the amount ofspring back. The size of the groove, for practical purposes, is notreadily measurable, but production may be controlled by the use of anordinary profilometer, even though the indicated groove depth obtainedfrom such an instrument may be a rather arbitrary figure. For example,it has been found that a satisfactory bobbin surface will give aprofilometer reading of (.51 about 20-40 micro inches (R.M.S.), using aconical Stylus with .0005 radius tip, Where an ungrooved bobbin ofsimilar construction and surface material will give a profilometerreading of about 4 micro inches (R.M.S.)

Without departing from the invention in its broader aspect, the groovingmay extend over the entire surface of the bobbin, although preferablythe end areas upon which no yarn is Wound are left smooth and ungrooved,as indicated in the drawing.

What is claimed is:

A textile package comprising a bobbin and yarn wound thereon, the bobbinhaving a yarn Winding surface comprising a microgroove indented in thebobbin surface, the

4 pitch of the groove being a small multiple of the yarn diameter andthe depth and width of the groove being a fraction of the yarn diameter,the yarn thickness being in a range from about 15 denier to about 70denier, the groove spacing being about .008 and the groove depth beingin a range from about .0001" to .091".

References Cited in the file of this patent UNITED STATES PATENTS

